Introduction

Often, strong contrast presents some difficulties for selecting the right
exposure. Either the sky is washed out, or the darker parts of the image are
more or less black. Like many other camera manufacturers, Sony offers a function
that "optimizes" the dynamic range of a photo. Typically, this function,
called DRO by Sony, leaves the bright part of the image unchanged and increases
the brightness of its darker parts. This can be done more or less
intensively (that is, with more or less signal amplification), but
in any case leads to more noise in the dark areas. Moreover, the images may
look somewhat "unnatural" and the colors may change somewhat (I found this
particularly with Ricoh cameras). The DRO function offers 5 steps which seem
to increase amplification by one light value (from LV1 to LV5). DRO should
only be used with lower ISO values because it increases the noise.

While DRO is based on one photo, the HDR technique combines several photo
to create an image with higher dynamic range. This limits the photos to static
subjects and may fail in some cases. It also takes some time for the processing
of the image. In addition, on the RX100 M4 you also get an unprocessed image
so that it is not necessary to take a "normal" image in case that
you do not trust the HDR result. In HDR mode, the RX100 M4 takes three images
with different EV settings, which you can set. The HDR photos may also look
somewhat "unnatural". The HDR function offers 6 steps which increase
the difference in EV values between the three shots (from +1 EV to +6 EV).
HDR cannot be used in RAW mode, but also with higher ISO values, because it
does not increase the noise.

Both, the DRO and the HDR function, offer an Auto mode that selects
the degree of amplification or EV separation automatically. Alexander White
and Martin Vieten recommend having the DRO Auto setting
enabled whenever you take general-purpose shots, particularly if you do not
want to do any post-processing.

The authors of the books about the RX100 M1 that I own judge these functions
differently - both have their opinions and preferences. Therefore, my recommendation
is to experiment with these functions, their settings, and decide on your own,
whether and how they are useful for you.

Sample Photos DRO

The following examples were taken to demonstrate the effect of increasing
DRO for the Sony RX100 M1 (including DRO automatic).

"Normal"

DRO Auto

DRO LV1

DRO LV2

DRO LV3

DRO LV4

DRO LV5

DRO Auto (repeated)

The motif may not be optimal, but indicates how the DRO function works. The Auto settings
seems to be fairly conservative.

Sample Photos HDR

The following examples were taken to demonstrate the effect of increasing
HDR strength for the Sony RX100 M1 (including HDR automatic).

"Normal" (same as next photo)

HDR Auto

HDR +1 EV

HDR +2 EV

HDR +3 EV

HDR +4 EV

HDR +5 EV

HDR +6 EV

HDR Auto (repeated)

"Normal" (same as previous photo; repeated)

The motif may not be optimal, but indicates how the HDR function works. The Auto settings
seems to be fairly conservative.

Conclusions

At the moment, I am experimenting with this feature and did not come to any
conclusions. It is however evident to me that the Auto settings have
the advantage of bringing slight improvements without making the image look
unnaturally. According to my impression, both
functions lead to unnaturally looking images beyond LV2/+2 EV.